irritating masses of
dirt, sweat, and hairs under the harness. They are most common under the
saddle, but may be found under collar or breeching as well. The sitfast
is a piece of dead tissue which would be thrown off but that it has
formed firm connections with the fibrous skin beneath, or even deeper
with the fibrous layers (fascia) of the muscles, or with the bones, and
is thus bound in its place as a persistent source of irritation. The
hornlike slough may thus involve the superficial part of the skin only,
or the whole thickness of the skin, and even of some of the structures
beneath. The first object is to remove the dead irritant by dissecting
it off with a sharp knife, after which the sore may be treated with
simple wet cloths or a weak carbolic-acid lotion, like a common wound.
If the outline of the dead mass is too indefinite, a linseed-meal
poultice will make its outline more evident to the operator. If the
fascia or bone has become gangrenous, the dead portion must be removed
with the hornlike skin. During and after treatment the horse must be
kept at rest or the harness must be so adjusted that no pressure can
come near the affected parts. (See also page 496.)

WARTS.

These are essentially a morbid overgrowth of the superficial papillary
layer of the skin and of the investing cuticular layer. They are mostly
seen in young horses, about the lips, eyelids, cheeks, ears, beneath the
belly, and on the sheath, but may develop anywhere. The smaller ones may
be clipped off with scissors and the raw surface cauterized with
bluestone. The larger may be sliced off with a sharp knife, or if with a
narrow neck they may be twisted off and then cauterized. If very
vascular they may be strangled by a wax thread or cord tied around their
necks, at least three turns being made around and the ends being fixed
by passing them beneath the last preceding turn of the cord, so that
they can be tightened day by day as they slacken by shrinkage of the
tissues. If the neck is too broad it may be transfixed several times
with a double-threaded needle and then be tied in sections. Very broad
warts that can not be treated in this way may be burned down with a
soldering bolt at a red heat to beneath the surface of the skin, and any
subsequent tendency to overgrowth kept down by bluestone.

BLACK PIGMENT TUMORS, OR MELANOSIS.

These are common in gray and in white horses on the naturally black
parts of the skin at the roots of t